The invention relates to systems and methods for mapping and ablating the interior regions of the heart for treatment of cardiac conditions.
Physicians make use of catheters today in medical procedures to gain access into interior regions of the body to ablate targeted tissue areas. It is important for the physician to be able to carefully and precisely control the position of the catheter and its emission of energy within the body during tissue ablation procedures.
The need for careful and precise control over the catheter is especially critical during procedures that ablate tissue within the heart. These procedures, called electrophysiological therapy, are becoming more widespread for treating cardiac rhythm disturbances.
During these procedures, a physician steers a catheter through a main vein or artery into the interior region of the heart that is to be treated. The physician then further manipulates a steering mechanism to place the electrode carried on the distal tip of the catheter into direct contact with the tissue that is to be ablated. The physician directs energy from the electrode through-tissue to an indifferent electrode (in a uni-polar electrode arrangement) or to an adjacent electrode (in a bi-polar electrode arrangement) to ablate the tissue and form a lesion.
Cardiac mapping can be used before ablation to locate aberrant conductive pathways within the heart. The aberrant conductive pathways constitute peculiar and life threatening patterns, called dysrhythmias. Mapping identifies regions along these pathways, called foci, which are then ablated to treat the dysrhythmia.
There is a need for cardiac mapping and ablation systems and procedures that can be easily deployed with a minimum of manipulation and effort.
There is also a need for systems and procedures that are capable of performing cardiac mapping in tandem with cardiac ablation. Such multipurpose systems must also be easily. introduced into the heart. Once deployed, such multipurpose systems also must be capable of mapping and ablating with a minimum of manipulation and effort.
A principal objective of the invention is to provide improved probes to carry out cardiac mapping and/or cardiac ablation procedures quickly and accurately.
Another principal objective of the invention is to provide improved probes that integrate mapping and ablation functions.
The invention provides a probe for use within the heart to contact endocardial tissue. The probe includes a catheter tube having a distal end that carries a first electrode element. The probe also includes a second electrode element on the distal end. The second electrode element defines a three-dimensional structure that extends along an axis and that has an open interior. The probe includes a mechanism for moving the first electrode element within the open interior of the second electrode element in a first direction along the axis of the second electrode element, in a second direction rotating about the axis of the second electrode element, and in a third direction normal to the axis of the second electrode element.
In a preferred embodiment, the movable first electrode element serves to ablate myocardial tissue. The second electrode element independently serves to sense electrical activity in endocardial tissue.
Other features and advantages of the inventions are set forth in the following Description and Drawings, as well as in the appended Claims.